1. Field of the Invention
This invention relates to an electromagnetic overcurrent tripping device for electric circuit breakers having a stationary magnetic yoke and an armature arranged movably relative thereto in which the distance of the armature from the surfaces of the poles of the magnetic yoke can be varied for setting different tripping currents.
2. Discussion of the Prior Art
A tripping device of this type is described, for instance, in U.S. Pat. No. 3,526,861. There, the distance of the armature from the pole surfaces of the magnetic yoke is adjusted by a plunger which can be actuated by a setting member which is adjustable at the housing of the circuit breaker. In contrast thereto, it is an object of the invention to provide a setting device for the armature which uses as few parts as possible and permits adjustment of the armature to a predetermined number of fixed tripping current levels.